Microsoft claims its newest iteration of IE is the most energy efficient, but "claim" is the operative word. When it comes to these types of tests, the proof is in the test methods. So how did Microsoft come to the conclusion that if you want to spare battery life, you have to use IE9? According to Mashable, Microsoft has run a series of tests that show IE9 makes the fewest demands on a computer's battery. When compared to Chrome 10, Firefox 4, Safari 5, and Opera 11, IE9 won out with FireFox 4 coming in second and Opera 11 coming in dead last. The tests included a baseline power consumption with no browser running, power consumption when the browser showed an about:blank page, power consumption when looking at a typical news content website, and power consumption when browsers ran Galactic and FishIE (performance tests created by Microsoft).

Electronista writes, "For the news site comparison, IE9 shaved 33 minutes from the theoretical life of a 56Wh battery when running the browser on a blank page. Chrome 10 reduced the run time by 1:07 hrs, showing the worst performance, while Firefox 4 took 31 minutes off the idle time. The HTML5 tests indicated similar results, with IE9 taking the lead and Firefox 4 coming in second. When all of the tests were combined, Microsoft claims IE9 battery life extended to 3:45 hrs. Firefox fell behind by 10 minutes, while Chrome 10 and Safari 5 were nearly an hour short and Opera 11 came in last."

However, Electronisa rightly points out that the numbers might be different if the benchmark tests were more varied, such as using different news sites for testing typical browsing scenarios and so on.

Also, to run IE9, you have to be running the Windows 7 OS. If the browser were being tested against others in different operating systems, it might not rank quite so high. Still, when an independent firm did a broader series of tests back in 2008, it did show IE8 as coming out on top, so there could be some credibility here.

So, should you rush to switch up your default browser to spare your battery? Maybe, if you already run Windows 7. Otherwise, we'd say don't worry too much about it. Firefox still seems to be one of the more energy efficient browsers you can use.